Originally Posted by flyerCO

The issue isn't the ticket or who sells it. The issue is how the flight is marketed. If it is sold as a codeshare (ie anything other then DL for the flight on DL metal) then can only do DoD upgrades to C+ or F. While it seems like they're the same flight, AF5678 operated by DL134 isn't the same as DL134. DL has zero control to change cabins for someone booked on a codeshare.

Remember this is basically you booking an AF flight that they know they won't be able to operate. This you are booked onto the "operating" airline that happens to operate a flight at the exact same time. Basically till DoD it is it's own flight for all purposes.